This invention relates generally to automatic door closing devices, and more specifically to a device designed to close sliding doors and screens.
With the increased use of sliding doors and screens in both commercial and residential buildings, the problem exists in maintaining these sliding doors and screens in a closed position when not in use to prevent any loss of energy associated with heating or cooling and to prevent any flying or crawling pests from entering the interior space of the building.
This problem is particularly prevalent in the domestic environment where sliding doors and screens are often utilized to provide access to porches, decks, backyards, patios, and pools. During the summer months when family activities are centered around those loci there is a constant flow of human traffic, especially when there are children involved, through these sliding doors and screens. It often occurs that children and adults leave these doors and screens open when entering or leaving the domicile either due to neglect or the necessity of the moment as when one's hands are full and closing the door would be quite awkward.
Various devices exist in the prior art which attempt to address themselves to these goals, and the state of the art of which the applicant is aware comprises the following U.S. Pat. Nos. 2,593,403--Bailey; 4,003,102--Hawks et al.; 4,126,912--Johnson; 4,301,623--Demukai.
None of these references contemplate singly nor render obvious in combination that which is taught and claimed in the instant application, since the patent to Demukai, Johnson, and Hawks et al. all teach the use of internally mounted springs, cables and pulleys which are integral with the door member itself and are incapable of being retrofitted without replacement of the entire door assembly. While each of the references teaches the use of a semi-automatic sliding door device with a tensioning spring or the like, none of the devices teach the use of a spring and air cylinder disposed at an angle relative to the direction of travel of the door, and further none has an arm which swings from a first to a second position, the arm having a roller disposed in a track. For example, the patent to Demukai teaches the use of a sliding door device with tension springs wherein a door is literally translated against spring tension 7 so that when the force used to open the door has been released, the spring will cause the door to move back to its closed position. See FIG. 1 for example. Similarly, the patent to Bailey teaches the use of a counter-balanced weight which causes the door to go from a first to a second position due to the work done by lifting the weight. Hawks et al. teaches the use of a spring or gravity motor having an override mechanism for a movable window or door including a pneumatic cylinder, a piston, a check valve admitting air to the cylinder, an override valve for permitting pressure damping of the air in the cylinder during movement of the door or window at a speed greater than the normal closing speed by the motor. That which is taught in the instant application is distinguished in that it is installed on the exterior surfaces of preexisting doors and screens, thus can be easily maintained and retrofitted to any existing sliding door or screen. Furthermore, the mechanical structure taught in the instant application is neither contemplated nor rendered obvious by any of the teachings in the citations.
Similarly the patent to Bailey teaches the use of a complex system of cables, pulleys and springs adapted to be use in a heavy duty commercial setting such as a mine, which does not fall within the purview of the instant application which is directed toward providing a simple and easily retrofitted automatic closing device for sliding doors and screens.